Macroevolution: Its all around us...

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the Bible was still around back in the time of the philosophers or whatever you prefer to call them.

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True, but the Bible definitely does NOT say that the Earth was a sphere.It says it is a disc.Hebrew has different words for "disc" and "sphere" and the word for "disc" is the one that is used to describe the earth.

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There are too many questions flying around. Let me make my point clear
Macroevolution-Evolutionary change involving large and complex steps resulting in a different KIND of animal

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What's a "kind"? Please give a precise definition, including the system I use to determine what "kind" to put a given animal or plant into?How do I tell one "kind" apart from another?

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Microevolution- a change within a single species resulting a different species or subspecies.

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Well, then, we have directly observed, both in the lab and in the field, new species branching off from the parent species. Here's one of my favorite examples:

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kind- if it looks like a housecat it's a house cat. If it looks like a tiger it's a tiger if it looks like an ape its an ape if it looks specifically like a human it's a human

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So, is this a housecat?

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What I'm saying is that you are talking about micro evolution not macro.

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Why is it that you use "kind" instead of "species" when describing "macro" versus "micro" evolution, respectively?What is the difference between "kind" and "species"?

I would address these protestations, but I think Schrafinator has already given you more than you can handle. Schrafinator: It looks like an ocelot 'kind' of cat to me.
I would like to see eclipse try and keep one as a house cat,
just because it sure 'looks like' one.As far as evidence of speciation in progress, that was my point in starting this whole thread. There is now plenty of evidence. Other good examples are given in posts 1, 2 and 11.This message has been edited by EZscience, 05-05-2005 07:36 AM

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It looks like an ocelot 'kind' of cat to me.
I would like to see eclipse try and keep one as a house cat,
just because it sure 'looks like' one.

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Nope, not an ocelot.

Is it an ocicat, intellegently designed to just look like an ocelot? LOL

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Asgara
"Embrace the pain, spank your inner moppet, whatever....but get over it"select * from USERS where CLUE > 0http://asgarasworld.bravepages.com
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Maybe it is an ocicat to eclipse.We'll see what he says it is if he ever returns.

But I remember reading the Just So Stories as a Child and wondering about the Djinn and India and Fishing And Cats.

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Aslan is not a Tame Lion

Hi eclipse, Please could you apply this logic to the pig photos I put up for you a few posts ago?I'm just curious to see which of those animals you consider to be micro-evolved pigs, and which are not pigs because they are too different from the archetypal pig you have in mind.One other thing you want to bear in mind - some different species look very similar to each other. take a look at these butterflies, for example. They are from different genera. Cheers!Mick

OK. You are the Cat expert.Still, it kind of looks like an ocelot 'kind' of cat, so maybe eclipse doesn't need any further clarification. Of course, that's not quite going to cut it for the rest of us.
Inquiring minds want to know the actual species....Is your cat then a 'fishing cat', Prionailurus viverrinus ?This message has been edited by EZscience, 05-05-2005 02:35 PM

Lets give eclipse some resources to help him research his assignment. MimicryConvergent EvolutionMaybe he will realize that overt similarity has no neccessary association with degree of relatedness. Edited by AdminJar to shorten linksThis message has been edited by AdminJar, 05-05-2005 10:36 AMThanks Jar - EZSThis message has been edited by EZscience, 05-05-2005 11:47 AM

I've been thinking about this. There appears to be a certain set of people who believe that microevolution can result in different breeds or cultivars within a single species, but that novel species cannot arise through such mechanisms.There must be examples from human agriculture and animal breeding where we have created cultivars or breeds that are not cross-compatible. In other words, breeds that are reproductively isolated from each other.For example, let's consider dogs. People opposed to macroevolution but happy with microevolution will accept that the existing canine breeds are the result of microevolution, mediated by selection from human breeders. Are there any breeds of dog that are reproductively isolated from each other?Let's imagine trying to mate a chihuahua with an Irish wolfhound. The chihuahua measures 6-9 inches from foot to shoulder. The Irish wolfhound measures 30-35 inches from foot to shoulder.Here are some pictures of them, drawn to scale: Is it physically possible for these two animals to have sex with each other and give birth to viable young? If not, that is evidence that microevolution can result in speciation. Does anybody know if this perverse experiment has been carried out? Does anybody know of reproductive isolation occuring between agrictultural cultivars?mick

You raise a good point.I think that morphological divergence in size could reach a point of being a physical barrier to gene flow in some cases.I think you would find genetic compatibility between your dogs
(and between either and a wolf, for that matter) but you might have to resort to artificial insemination to demonstrate it !But if you were to populate an island with, say 2 pairs of each plus a sustainable food supply and return after 1000 generations or so, you *might* find you had two separate species. Otherwise, you would probably find an interbreeding population with intermediate morphology.The key to speciation is reproductive isolation so I think you could use articifial selection within a species to generate forms that would be reproductively isolated from each other *physically* even though they would still be genetically cross-compatible. This might take only a few generations of selectively breeding for divergence in size, but actual *genetic* isolation would take many, many more generations.In regard to plant cultivars, I don't think you will find any examples of speciation from agriculture, simply because traditional plant breeding techniques involve multiple back crosses to parental types whenever new varieties are developed. The whole enterprise of conventional cultivar development hinges on keeping the plant species intact so that one can always return to a collection of 'heirloom' varieties to obtain some unique genetics, if needed. If one was to let reproductive barriers develop among varieties, it would defeat the whole purpose of having a large bank of genetic information to draw on.But the big answer is likely yes - careful manipulation of micro-evolution by means of artifical selection should be able to *create* effectively separate species, although man would be their 'creator' of course.

I think if you put some irish wolfhounds and some chihuahahs on an island together, the chihuahuas would have mysteriously vanished by the next day. The wolfhounds are very scary dogs. Instead of barking, they make a kind of continuous low hungy wailing sound. And they look permanently hungry.I'm not sure i would put too much emphasis on genetic compatibility when we define species. There are plenty of species within mammalia that can crossbreed, but never do in nature, because they have different mating songs, different mating dances, different sexual coloration or aromas, etc. This behavioural/morphological isolation is quite common in the bats and rodents, for example. Genetic incompatibility is just one isolating mechanism amongst many.

As a dog lover I have always wondered what it would be like to own a wolfhound. (But I have a short-haired pointer now and she is quite enough to handle).But you are right - they would probably eat the chihuahuas.
I was just extrapolating on your 'physical size can isolate' idea.
I think it can work.Also, I didn't mean to imply that genetic incompatibility was the most important mechanism of speciation in nature - obviously behavioral mechanisms can be very important in reproductive isolation.But it is sort of the final step in the speciation process.

Let me see if I understand this. Youre saying that insects that feed on a particular plant will only mate with insects of their same kind that also eat in that particular plant. This process called "host plant fidelity" will make these insects become into a new species. Am I right?Can something like this happen to humans? does this mean that if I only have sex with women that live in the same town that I do or eat exactly the same food I eat we can then make a new species by isolating ourselves from people on neighboring towns to the extent thst the new species created would not be able to have sex with someone from europe, africa or somewhere else in the world?School me on this please

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Viva Puerto Rico Libre. Colonialism is an international crime

It is not going to work quite like that for humans.Keep in mind that this mechanism is contingent on some life history constraints that are specific to the insects in question.They have one or 2 generations per year, all adults of each generation mating within about a week or two of emergence.The borer larvae spend their whole life developing in the stalk of a single plant - they are not free-living, so they cannot change plants - mom chooses one and they are stuck with it.If the adult insects emerge from one kind of plant (say, corn) and then orient specifically to that kind of plant to seek mates, then they will only mate with others that have emerged from corn.Now say we have another group of the same insect species that began feeding on another plant (say a weed species) at some time when corn was not available. Their offspring likewise orient to the plants they fed on as larvae (this 'Hopkins' effect' is actually not essential to the process, but it helps to simplify the explanation) and seek their mates on those plants.In this case, we would rapidly evolve two sympatric populations (same range) that don't interbreed anymore, simply because they are orienting to different plant species to find mates. The stronger the host plant fidelity effect, the less the gene flow between the populations every generation, and the faster populations will diverge genetically. This can happen purely by chance (genetic drift gradually separating the populations), but could also be hastened by disruptive selection (different genes being favored on each of the two plant species, because selection pressures differ between the plants.Human populations are not likely to be susceptible to such a process.
We just don't have the same life history constraints that make it possible.We are not monophagous (eating only one plant for our entire juvenile life) nor are we monogamous in most cases (many female moths mate usually only once and get about the business of laying eggs imediately). Plus we have far greater dispersal capabilities (think continents as opposed to corn fields) and are exceedingly long lived (by comparison).These are all things that reduce the chance that any population of humans will ever become reproductively isolated from any other, although I suppose you could postulate the rapid fixation of some absurd mating ritual in some culturally segregated population.Remember that the speed of evolution in a population is also a function of the generation time of the organism, so speculations on possible trajectories of human evolution must be considered on time scales of many thousands of years to be at all realistic w/r/t any meaningful evolutionary changes. 1000 yrs = ca. only 50 human generations (assuming a median age of 20 at first reproduction) a mere blip in evolutionary time.I hope this clarifies the post a bit.PS: Veo que tu eres Mayaguezano.
Yo vivi ahi por casi un ano y me gusto mucho.
Me estrano las playas aqui en Kansas !This message has been edited by EZscience, 05-05-2005 02:24 PM